Question 20

Created on Tue, 05/12/2015 - 05:55
Last updated on Fri, 08/12/2016 - 21:19
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A 53-year-old male presents following a motor vehicle accident. He complains of severe abdominal pain but has no chest or long bone injuries. He has previously had a mechanical mitral valve replacement. His medications include warfarin.
The following image is a slice from his CT body scan.

a) List the abnormalities on the CT scan image.
 
b) Outline the advantages and disadvantages of CT scanning in the assessment of blunt abdominal trauma.
 
c) Outline your immediate management of his coagulation state.
 

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College Answer

a)

  • Ruptured liver
  • Free intraperitoneal fluid (blood) +++

b)

  • Advantages: non-invasive; ability to exclude retroperitoneal injuries; ability to grade solid organ injury; shows were where the intra-abdominal blood is coming from; may reveal associated pelvic and spinal injuries; ability to detect clinically unsuspected injuries
  • Limitations: radiation dose; the need to give intravenous contrast; relatively poor sensitivity for hollow viscus, mesenteric, retroperitoneal, and diaphragmatic injuries; difficulty getting an unstable patient to the CT scanner.

c)

Competing interests of life-threatening haemorrhage and need for anticoagulation (MVR) and in this instance haemorrhage is greater risk

Cease warfarin therapy and give:

Vitamin K 5 – 10 mg IV (recommended in Australian guidelines but controversial as may cause resistance when warfarin needs re-starting. Balance of risks and lower dose may be preferable)

AND

Prothrombin complex concentrate (Prothrombinex-VF) 50 IU/kg AND

Fresh frozen plasma 150 – 300 ml OR If PCC not available

FFP 15 ml/kg 
Tranexamic acid as soon as possible

Other blood products (packed cells, platelets, cryoprecipitate) as indicated Titrate therapy against measurement of coagulopathy (APTT, PT, fibrinogen, platelets)

TEG if available 
Prevent / correct hypothermia, acidosis, hypocalcaemia

Discussion

The image above is not from the original exam paper, but rather stolen shamelessly fromRadiopedia.org. It represents a large laceration in the right lobe of the liver, with a perihepatic hematoma.

Now, as for the advantages and disadvantages of CT in blunt abdominal trauma;

a good recent article discusses these points as well as offering tables of injury severity grading.

  • Advantages of CT:
    • Rapid
    • Non-invasive
    • Readily available
    • Allows assessment of clinically undetectable injuries
    • Good sensitivity for solid organ damage
    • Contrast extravasation can suggest the source of bleeding
  • Disadvantages of CT:
    • Radiation exposure
    • Contrast exposure
    • Exposure of the patient to the risk of transfer
    • Poor sensitivity for hollow organ damage

As for the corection of coagulopathy; the answer should at least include the competition between the need for anticoagulation and the need for haemostasis. If one bleeds to death, one's circulation will cease and with blood stagnating in the left atrium those valve leaflets will get clot on them anyway, so perhaps the haemostasis is a priority.

The discussion of haemostasis in this patient can be divided into two subtopics: what to do about the warfarin, and what generic strategies are there to achieve medical haemostasis in a trauma patient.

Reversal of warfarin anticoagulation

A generic discussion of warfarin reversal guidelines takes place in another chapter, and Question 15.1 from the second paper of 2011 deals with the reversal of warfarin in a patient with a suprathereapeutic INR.

In brief, this is a warfarinised patient with clinically significant bleeding, and thus it does not matter what his INR is. The most recent guidelines suggest the following multi-agent strategy:

  • 5-10mg of Vitamin K
  • prothrombinex 50.0 units/kg
  • FFP 150–300mL.

Medical haemostasis in major trauma

The use of tranexamic acid in trauma is also well-established, and one would administer 1g of this substance immediately.

The college points out that TEG would be the ideal means of assessing the coagulation system (and fibrinolysis), but this is still being debated.  If TEG is not available (and it is infrequently available) then PT APTT and fibrinogen levels would guide one's resuscitation.

There is widespread disagreement as to what proportion to give; typically one is guided by the volume of blood transfused and by the changes in coagulation parameters.

Ultimately, one might arrive at a situation where Factor VIIa is pulled out, in spite of this being an off-license use of this product. This controversy is better discussed in Question 12 from the first paper of 2007, where the college invites us to "white short notes" about it.

References

Fang, Jen-Feng, et al. "Usefulness of multidetector computed tomography for the initial assessment of blunt abdominal trauma patients." World journal of surgery 30.2 (2006): 176-182.

Soto, Jorge A., and Stephan W. Anderson. "Multidetector CT of blunt abdominal trauma." Radiology 265.3 (2012): 678-693.

Ross I Baker, Paul B Coughlin, Hatem H Salem, Alex S Gallus, Paul L Harper and Erica M WoodWarfarin reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis Med J Aust 2004; 181 (9): 492-497.

There is also this local policy document.